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  • FIRST POST
    • Former MSE Helen
    • By Former MSE Helen 27th Apr 12, 8:34 AM
    • 2,324Posts
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    Former MSE Helen
    MSE News: Government miles-per-gallon car figures 'unreliable'
    • #1
    • 27th Apr 12, 8:34 AM
    MSE News: Government miles-per-gallon car figures 'unreliable' 27th Apr 12 at 8:34 AM
    This is the discussion thread for the following MSE News Story:

    "Official government fuel figures overstate just how many miles cars can do to the gallon, it has been claimed"

Page 1
    • verityboo
    • By verityboo 27th Apr 12, 8:43 AM
    • 966 Posts
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    verityboo
    • #2
    • 27th Apr 12, 8:43 AM
    • #2
    • 27th Apr 12, 8:43 AM
    Not really news, just another report confirming what people knew - the manufacturer tests carried out under ideal conditions give better mpg than people achieve in the real world
    • agrinnall
    • By agrinnall 27th Apr 12, 8:57 AM
    • 22,820 Posts
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    agrinnall
    • #3
    • 27th Apr 12, 8:57 AM
    • #3
    • 27th Apr 12, 8:57 AM
    In what way are they 'Government figures' anyway - surely they are figures provided by the manufacturers and just compiled by the Department of Transport?
    • fivetide
    • By fivetide 27th Apr 12, 8:57 AM
    • 3,676 Posts
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    fivetide
    • #4
    • 27th Apr 12, 8:57 AM
    • #4
    • 27th Apr 12, 8:57 AM
    Yep a definate "no excrement Sherlock" story.

    In other news, grass green, sky blue and later, night to follow day.

    5t.
    • Strider590
    • By Strider590 27th Apr 12, 9:25 AM
    • 11,622 Posts
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    Strider590
    • #5
    • 27th Apr 12, 9:25 AM
    • #5
    • 27th Apr 12, 9:25 AM
    Well.... To be fair it's been in the govts interest to not challenge the manufacturers claimed MPG figures, many people wouldn't be buying cars and thus feeding into the coffers if they didn't think their potential new car would give them some benefit in fuel consumption.
    Why else was it so important that the govt set about creating the scrappage scheme a few years back?

    They are of course idiots anyway, if they think buying a new car can save them money at all.... Even if the old one did 35mpg and the new one 50mpg.
    I may not agree with you, but I will defend to the death your right to make an a** of yourself.

    <><><><><><><><><<><><><><><><><><><><><><> Don't forget to like and subscribe \/ \/ \/
    • RDG
    • By RDG 27th Apr 12, 10:03 AM
    • 211 Posts
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    RDG
    • #6
    • 27th Apr 12, 10:03 AM
    • #6
    • 27th Apr 12, 10:03 AM
    Yeah this really isnt news, manufacturers make claims for figures but they will have done the test under very specific circumstances that are probably impossible to achieve in reality. Hence I always look at the combined figure and deduct 10% for possible real world driving.

    Although on my commute I do get the manufacturers claimed figure for the combined cycle which is what i would describe my journey as. It all depends on how people drive it should be treated as a potential figure. In reality if you drive the right way you can exceed these manufacturers figures in some cars.
  • adamc260
    • #7
    • 27th Apr 12, 10:20 AM
    • #7
    • 27th Apr 12, 10:20 AM
    When I buy a car I look at Urban and assume that will be about the average I get... maybe a bit higher. That way i'm looking at the bottom end of the scale.
    • Strider590
    • By Strider590 27th Apr 12, 10:29 AM
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    Strider590
    • #8
    • 27th Apr 12, 10:29 AM
    • #8
    • 27th Apr 12, 10:29 AM
    When I buy a car I look at Urban and assume that will be about the average I get... maybe a bit higher. That way i'm looking at the bottom end of the scale.
    Originally posted by adamc260
    Reality is often around 10% less than the "combined" figure.
    I may not agree with you, but I will defend to the death your right to make an a** of yourself.

    <><><><><><><><><<><><><><><><><><><><><><> Don't forget to like and subscribe \/ \/ \/
    • jeferey
    • By jeferey 27th Apr 12, 10:45 AM
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    jeferey
    • #9
    • 27th Apr 12, 10:45 AM
    • #9
    • 27th Apr 12, 10:45 AM
    We've known this for ages! - as Strider said most people get less.
    I hypermile to get 30+% more than combined figure for my car.

    In what way are they 'Government figures' anyway - surely they are figures provided by the manufacturers and just compiled by the Department of Transport?
    Originally posted by agrinnall
    The secrets behind official mpg v real life mpg
    Last edited by jeferey; 27-04-2012 at 10:49 AM.
    If at first you don't succeed, try, try, try - oh bu99er that just cheat
    • colino
    • By colino 27th Apr 12, 10:48 AM
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    colino
    The only point for these tests is to compare other cars in the way they have performed in the same test. So you can see with your reading eyes on that a Panda is more economical than a Bentley, that's their only value.
    My wifes car persistently hovers around 23mpg and if I take it for a week the average for that fill will be 31-32mpg. Same car, same roads, just different driver.
    The manufacturers don't fake the figures (albeit the one production car they test will be in finest fettle), as they aren't so daft as to be officially sanctioned, but real life will always be different.
    • fivetide
    • By fivetide 27th Apr 12, 11:09 AM
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    fivetide
    Also, lets not forget the tests are performed in a lab and often the engine isn't even in the car.

    Nothing like realistic conditions.

    that said, Watchdog did a big piece on this a while ago and followed a group of people on an mpg challenge. One chap had actually got more than the official figure from his smart car!

    5t.
    • cepheus
    • By cepheus 27th Apr 12, 11:13 AM
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    cepheus
    "The vehicles were then driven by two experienced engineers over a variety of roads"
    Unfortunately you need a wider range of drivers to get representative figures. Other major influential factors include the amount of start drop driving (sometimes proxied by average speed), and journey length which partly determines the proportion of distance/time the car spends warming up.

    The driving cycles used to measure fuel consumption are designed to simulate these to an extent, but there are so many factors.

    How is the fuel consumption test conducted?
    • The test is outlined in Directive 93/116/EC as amended by Regulation (EC) 692/2008, and provides results that are more than representative of actual average on-road fuel consumption than previous tests. There are two parts: an urban and an extra-urban cycle. The cars tested have to be run-in and must have been driven for at least 1,800 miles (3,000 kilometres) before testing.
    • Urban Cycle
      The urban test cycle is carried out in a laboratory at an ambient temperature of 20oC to 30oC on a rolling road from a cold start, i.e. the engine has not run for several hours. The cycle consists of a series of accelerations, steady speeds, decelerating and idling. Maximum speed is 31mph (50km/h), average speed 12mph (19km/h) and the distance covered is 2.5 miles (4km).
    • Extra-Urban Cycle
      This cycle is conducted immediately following the urban cycle and consists of roughly half steady-speed driving and the remainder accelerations, decelerations, and some idling. Maximum speed is 75mph (120km/h), average speed is 39mph (63 km/h) and the distance covered is 4.3miles (7km).
    • Combined Fuel Consumption Figure
      The combined figure presented is for the urban and extra-urban cycle together. It is therefore an average of the two parts of the test, weighted by the distances covered in each part
    Last edited by cepheus; 27-04-2012 at 11:23 AM.
    • camaj
    • By camaj 27th Apr 12, 11:19 AM
    • 496 Posts
    • 241 Thanks
    camaj
    Seems like this is PR for What car? than anything else. Any test can be disputed, the point is that all cars must go through identical tests, that is the scientific way of doing it. This allows buyers to assertain what cars are more fuel efficient.

    I see that What Car? neglect to mention that some people are able to get better economy than the official figures. The world record in economic driving is something like 30-40MPG higher than the official MPG for that car, which I believe is a VW Passaat
    • alleycat`
    • By alleycat` 27th Apr 12, 11:22 AM
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    alleycat`
    My major confusion is why my old VW could do better mpg than my "new" eco version (that has much higher quoted mpg).
    In fact i could beat the manufacturer figures in the old car (passat).

    No such luck in the newer model (I can barely get within -10%).

    The above is based on tank to tank driving on pretty much the same roads over the last decade.

    The stuff coming out of the pipe is cleaner (euro III to euro V) but does the offset in reduced mpg make it an exercise in number fiddling?
    • withabix
    • By withabix 27th Apr 12, 11:42 AM
    • 8,959 Posts
    • 7,908 Thanks
    withabix
    As per cepheus's post above, the test is to blame, not the manufacturers or the government.

    The test figures are a means of comparing different vehicles under fixed conditions and nothing more.

    If you want to blame anyone, blame the European Commission - they made the rules.

    To be honest, I don't know why MSE have re-published this non-story.
    British Ex-pat in British Columbia!
  • Notmyrealname
    Not really news, just another report confirming what people knew - the manufacturer tests carried out under ideal conditions give better mpg than people achieve in the real world
    Originally posted by verityboo
    So why do I regularly exceed them?
  • Dave_C
    Not a comment on the story, but the headline Government miles-per-gallon car figures 'unreliable' is particularly cringe-worthy. Ignoring the unnecessary hyphens, there are such well-known phrases as "fuel economy" and "fuel consumption" which would be much better.

    Dave
    • Reaper
    • By Reaper 27th Apr 12, 12:39 PM
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    • 5,000 Thanks
    Reaper
    Not sure why the news article about didn't provide a link to the site it is talking about. Here you go:
    http://www.whatcar.com/truempg
  • MeanParent
    This is a real problem for company car drivers who are refunded mileage by their employers with rates set by HMRC which are based on these inaccurate figures.

    This means that many are seriously out of pocket and there is nothing that can be done. (I have contacted HMRC about this as my car costs 25 pence per mile in fuel but can only claim back 19 pence per mile).
    • colino
    • By colino 27th Apr 12, 4:20 PM
    • 4,936 Posts
    • 2,514 Thanks
    colino
    MeanParent first thing is that running around in your own car costs you a darn sight more than the petrol costs, don't do it unless you are properly recompensed! Additionally if they only pay you 19ppm, check out Mileage Allowance Relief.
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